Boston city officials have announced improved public safety measures for the final two miles of the world's oldest marathon, a year after two explosions near the finish line killed three people and wounded 260 others.
Mayor Martin Walsh and Police Commissioner William Evans on Saturday said more uniformed and undercover police officers will be deployed along the marathon route in Boston.
Authorities also have installed more than 100 cameras along the Boston portion of the marathon route, together with 50 observation points that will help to monitor the crowd.
Thirteen ambulances will be deployed along the Boston portion of the marathon, together with 140 emergency medical service workers on foot patrol, bicycles, utility vehicles and in medical tents.
Officials urge spectators to leave backpacks, strollers and other large items at home.